1. Field of the Invention
The present invention relates generally to tape libraries using auxiliary memory devices contained in tape storage cartridges to maintain information related to tape cartridge verification.
2. Description of Related Art
Data storage libraries, such as tape libraries, are typically used to store and retrieve large amounts of data for data manipulation and archiving purposes. These libraries are generally comprised of drive devices adapted to write data to and read data from tape cartridges that are often housed within the tape libraries. In the interest of obtaining cursory information about a specific tape cartridge without requiring a time-consuming media load and tape threading process to read the on-tape index file, techniques using holes arranged in patterns in the cartridge casing and later electrical pads grounded in a variety of combinations were introduced. The holes and/or electrical pads provided simple information such as the tape capacity and the manufacturer identity. Today, these techniques are yielding to the introduction of radio frequency chips located in the tape cartridges, called a Memory-In-Cartridge (MIC) also known as a Medium Auxiliary Memory (MAM). FIG. 1A shows an example of a tape cartridge 100, tape medium 102, and MAM 104 (shown here in dashed lines). The tape medium 102 is an illustrative embodiment of an addressable storage medium to which data is stored and from which stored data is retrieved in accordance with embodiments of the claimed invention. An addressable storage medium is “addressable” in that storage locations are demarcated by storage addresses, be they physical addresses (such as physical block addresses, PBAs) or logical addresses (such as logical block addresses, LBAs). A plurality of storage elements each employing a separate addressable storage medium can be combined to form a data storage array. Although a tape medium is used for purposes of this description, the claimed embodiments are not so limited such that in equivalent alternative embodiments the addressable storage medium encompasses other types of storage media such as but not limited to magnetic data storage disks, optical data storage disks, solid state memory, and the like. The MAM 104 and tape medium 102 reside in the interior of the cartridge 100. In this example, the MAM is disposed in an LTO-3 cartridge which can be provided by TDK Corp. of Tustin, Calif.
A MAM allows the tape drive to access valuable cartridge data without the use of a physical connection, reducing connector wear for both the drive and the media. The MAM comprises a memory chip built into the data cartridge that provides a direct and immediate connection to the drive's on-board processors, which speeds access to information related to the data cartridge such as system logs, for example. Information and file search parameters are formatted within the MAM system thereby effectively cutting the data access time down to a fraction from historical techniques.
As shown in FIG. 1B, a MAM 104 fundamentally comprises an integrated circuit that includes solid state memory and a transponder 124 attached to an antenna 126, which is typically a small coil of wires. The MAM 104 is considered a passive device because it is energized when subjected to a sufficiently strong RF field, generated by a MAM-Reader. Information can be transmitted between the MAM and the MAM-Reader via a specific radio frequency.
Though a MAM is capable of storing data, the amount of data stored on a MAM is relatively miniscule compared to that stored on the tape medium 102. As such, a MAM device, in the exemplary configuration, cannot reasonably function as a backup device that stores duplicate data stored on the tape medium 102. Currently, data verification on a tape medium is done by comparing the data stored on a tape medium 102 with a duplicate copy stored on either a different tape medium or another storage device, such as a disc drive. Hence, if data is corrupt or missing because of damage to the tape medium, such as delamination of the magnetic thin film from the polymer tape substrate, damage due to contamination, or some other malfunction, knowledge of data corruption can be accomplished by comparing the data with the copy of the data. Unfortunately, maintaining a duplicate copy of data for the purposes of data verification is a resource-consuming approach.
In an effort to expand capabilities of a storage element containing a MAM operable for the purpose of improving data verification of tape cartridges 100, methods and apparatus are disclosed herein. It is to innovations related to this subject matter that the claimed invention is generally directed.